4.1 Capacity vs. constraints

Although the project examines both "capacity and constraints," in many cases, constraints are simply the reverse of capacity: the environmental, infrastructure, and financial limits that can influence the scale of settlements and their ability to accommodate growth. Table 1 indicates some ways of defining and determining capacity and constraints in water and wastewater services.

Table 1: Types of capacity and constraints data

Types of capacity data	Types of constraints data
Designed capacity of a water or wastewater plant Scale and extent of major water and sewer pipes Number of connections, and/or population served Average and maximum flows through a plant Reserve capacity Plant classification Aquifer capacity and water takings from aquifers Surface water body capacity Assimilative capacity of water bodies receiving effluent	Groundwater limits Surface water limits Type of water bodies receiving effluent Assimilative limits of water bodies receiving effluent Limits on subsurface sewage disposal Inflow and infiltration data Plant and system costs - capital, operations, lifecycle Drought data; climate change data Age of water and wastewater system elements Evidence of failure in water and wastewater systems